A strut-type suspension used for a front wheel of an automobile has structure in which a strut assembly comprising a piston rod and a hydraulic shock absorber is combined with a coil spring. When a steering is operated, the strut assembly is rotated together with the coil spring. Accordingly, to support a load applied to the strut-type suspension while allowing smooth rotation of the strut assembly, usually a bearing is placed between an upper mount which is a mounting mechanism for mounting the strut assembly onto the automobile body, and an upper spring seat which is a spring seat for the upper end of the coil spring.
For example, the Patent Literature 1 discloses a slide bearing for a strut-type suspension. This slide bearing comprises: an upper case which is mounted on the side of an upper mount; a lower case which is mounted on the side of an upper spring seat and is rotatably combined with the upper case; and an annular center plate and an annular sliding sheet which are placed in an annular space formed by combining the upper case and the lower case.
Here, the upper case has an annular load transmission surface which forms an upper surface of the annular space formed by combination of the upper case and the lower case. The center plate is formed of plastic (synthetic resin) including at least one of polyamide resin, polyolefin resin, and fluorine resin, and has an annular bearing surface which supports a load transmitted from the load transmission surface of the upper case via the sliding sheet. This bearing surface has an annular recessed portion formed in a circumferential direction, and the recessed portion is filled with lubricating grease. The sliding sheet is formed of plastic including at least one of polyamide resin, polyester resin, polyolefin resin, polycarbonate resin, and fluorine resin. The sliding sheet is placed between the load transmission surface of the upper case and the bearing surface of the center plate, and has a sliding surface that comes in slidable contact with the bearing surface of the center plate.
The slide bearing of the above structure supports a load applied to the strut-type suspension by the bearing surface of the center plate via the load transmission surface of the upper case and via the sliding sheet. Further, the lubricating grease filled in the recessed portion of the bearing surface of the center plate lubricates the bearing surface of the center plate and the sliding surface of the sliding sheet pressed against the bearing surface by the load applied to the strut-type suspension, to allow thereby smooth rotation of the strut-assembly.